1. Field of the Invention
The present invention relates to an image processing apparatus which divides an image into a plurality of areas, an image processing method, and a computer-readable recording device.
2. Description of the Related Art
Conventionally, an endoscope has been widely used as a medical observation device which is inserted to an inside of a body of a subject such as a patient and allows non-invasive observation of an inside of a lumen. In recent years, a swallowable endoscope (capsule endoscope) which houses an imaging device, a communication device, and the like in an inside of a capsule-shaped casing and wirelessly transmits image data captured by the imaging device to an outside of the body has also been used.
An observation of and a diagnosis on the images obtained by the medical observation device are difficult tasks requiring a lot of experiences and efforts. Especially, since the number of successive images (intraluminal images) obtained in one examination becomes huge (not less than several tens of thousands of images) in the case of a capsule endoscope, a burden imposed on a doctor who makes a diagnosis is heavy. Therefore, medical diagnosis supporting functions which assist a diagnosis by a doctor have been desired. As one of such functions, an image recognition technique in which an abnormal site and the like are automatically detected from intraluminal images and an image which needs to be intensively diagnosed is indicated has been proposed.
By the way, it is of significance, as a preprocessing in detecting an abnormal site and the like by the image recognition, to eliminate an area which captures a residue and the like and is unnecessary for the observation and to extract a mucus membrane area. As a technique concerning an area division (segmentation) of an image, a method of extracting a segment having a predetermined feature based on color information and edge information in each of pixels constituting an image is disclosed in Japanese Patent Application Laid-Open No. 2007-172224, for example. More specifically, a predetermined segment is extracted by obtaining an energy function based on a probability indicating that pixel data shows a color in a predetermined segment and based on a relation between pixel data of pixels adjacent to each other (whether or not an edge is present between neighboring pixels) and minimizing the energy function in Japanese Patent Application Laid-Open No. 2007-172224.